More than 18,000 people from all different agencies across the Northwest participated in the first ever Cascadia Rising exercise.
It's the largest scale training scenario ever done in the United States, mimicking the effects of a catastrophic 9.0 magnitude earthquake and the tsunami that follows hitting the west coast.
"People are going to be traumatized by this. The modeling that we use shows about 1 to 2 million people on the western side of Oregon and Washington that will probably be homeless," said Ken Murphy, regional administrator of FEMA.
While the damages from the earthquake in Idaho will likely not be significant, it doesn't mean the Gem State will come out unscathed.
"What we do expect is people trying to get away from the disaster that is happening. On the west coast of Washington and Oregon, they've only got one place to run, and that's to Idaho," said Governor Butch Otter.
It may just be a drill now, but the Cascadia Rising scenario took in real time events like weather, fires and other ramification from a large-scale earthquake.
"In going through this exercise we are going to be able to determine where we are not as efficient as we should be," said Governor Otter.
By making it as real as possible, Governor Otter said how well we practice is going to be how well we do during the real thing.
"Think about what would happen to any Idaho community that all of the sudden overnight got 50,000 more residents," said Murphy.
"We have to be prepared to house those people, we have to be prepared to help those people get food and safety," said Governor Otter.
Officials said there is only so much they can control in the event of a natural disaster, It's up to each individual to make sure they are prepared.